Atomistic-object kinetic Monte Carlo simulations of irradiation damage in tungsten

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http://hdl.handle.net/10138/307861

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Mason , D R , Sand , A E & Dudarev , S L 2019 , ' Atomistic-object kinetic Monte Carlo simulations of irradiation damage in tungsten ' , Modelling and Simulation in Materials Science and Engineering , vol. 27 , no. 5 , 055003 . https://doi.org/10.1088/1361-651X/ab1a1e

Title: Atomistic-object kinetic Monte Carlo simulations of irradiation damage in tungsten
Author: Mason, D. R.; Sand, A. E.; Dudarev, S. L.
Contributor organization: Materials Physics
Department of Physics
Date: 2019-07
Language: eng
Number of pages: 23
Belongs to series: Modelling and Simulation in Materials Science and Engineering
ISSN: 0965-0393
DOI: https://doi.org/10.1088/1361-651X/ab1a1e
URI: http://hdl.handle.net/10138/307861
Abstract: We describe the development of a new object kinetic Monte Carlo (kMC) code where the elementary defect objects are off-lattice atomistic configurations. Atomic-level transitions are used to transform and translate objects, to split objects and to merge them together. This gradually constructs a database of atomic configurations-a set of relevant defect objects and their possible events generated on-the-fly. Elastic interactions are handled within objects with empirical potentials at short distances, and between spatially distinct objects using the dipole tensor formalism. The model is shown to evolve mobile interstitial clusters in tungsten faster than an equivalent molecular dynamics (MD) simulation, even at elevated temperatures. We apply the model to the evolution of complex defects generated using MD simulations of primary radiation damage in tungsten. We show that we can evolve defect structures formed in cascade simulations to experimentally observable timescales of seconds while retaining atomistic detail. We conclude that the first few nanoseconds of simulation following cascade initiation would be better performed using MD, as this will capture some of the near-temperature-independent evolution of small highly-mobile interstitial clusters. For the 20keV cascade annealing simulations considered here, we observe internal relaxations of sessile objects. These relaxations would be difficult to capture using conventional object kMC, yet are important as they establish the conditions for long timescale evolution.
Subject: radiation damage
lattice defects
microstructural evolution
kinetic Monte Carlo
MOLECULAR-DYNAMICS
RADIATION-DAMAGE
CASCADE DAMAGE
DISLOCATION LOOPS
INTERSTITIAL ATOM
EVOLUTION
CLUSTERS
DIFFUSION
DEFECTS
VACANCY
114 Physical sciences
Peer reviewed: Yes
Usage restriction: closedAccess
Self-archived version: submittedVersion


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